Once the site of the Rupert Brewery, the one-acre park is squeezed between high-rises at 92nd and 93rd streets and Second and Third avenues. It’s the only park that provides a playground, tennis, handball and basketball courts in the densest neighborhood of the city.

Related bought the site from the city Department of Housing Preservation and Development for $10 million in 1983 under an urban-renewal plan to revitalize the area. Under the agreement, it had to clean up and maintain the park for public use through June 20, 2008. Related continued to keep it open to the public until last month.

One plan on the drawing board is for Related to build a 49-story tower in the park’s footprint, but so far, the company has held off on demolition work, leaving a small window open for negotiations.

Related was getting tax breaks for the playground’s upkeep but is now asking for several million dollars more in tax breaks for an adjoining property, the older luxury rental Carnegie Park, according to a city source.

In exchange for the breaks, Related would give the playground back to the city, according to several sources.

City Council member Dan Garodnick confirmed that Related had said it “had a meeting with the city, and had explored the possibility of working out a deal to keep the playground open in exchange for a either a tax incentive or some benefit from the city. Apparently, there was no interest.”

A company spokeswoman declined to comment.

“This administration has the chance to reverse an irresponsible deal for a desperately needed park that never should have been sold in the first place,” said Geoffrey Croft, of NYC Park Advocates.

The closure has outraged thousands of residents who have been fighting to keep the park open.

“I feel as if we were being held hostage,” said Oscar Fernandez, 36 whose son Ryan, 5, grew up playing in the tot lot.

“Basically, it’s selfishness and greed that rules the day,” he said.

Garodnick, City Councilwoman Jessica Lappin, and about 150 local residents held a rally two weeks ago to save the park, asking the city to reacquire the land.

The Mayor’s Office did not comment.

Related Companies recently doled out $1 billion for the Hudson Yards, the 26-acre swath of rail yards on the West Side that it wants to develop into 12 million square feet of office towers, residential buildings and parks.